Today, infomercials are the means, and retail is the end. For every unit sold through a telephone operator standing by, three-to-10 are sold in retail stores, according to the Electronic Retailing Association, which represents the $50 billion "direct response" industry.

"Infomercials are the only way to get a product into distribution," says Michael Wales, the daddy of Grill Daddy, a grill brush that successfully made the voyage from Saturday morning TV to hardware store aisles. "Walmart is selling name products supported by big advertising campaigns. If you go on TV and create a brand, then they're interested."

A successful As Seen On TV campaign not only creates a windfall profit, it creates a high.

"I get very excited when we come up with a big hit," says A.J. Khubani, the self-anointed King of Infomercials whose Telebrands company has laid 30 million PedEgg foot files. "It's the rush of success ... And the payoff can be very big."

As Seen on TV products claim to scratch every itch -- real or imagined. But for every 20 products that hit the air, 19 will fall flat, says Steve Heroux, who developed the As Seen on TV hits Wonder Hanger and Twin Draft Guard.

To get a shot at success, a product must either save time, save money or solve a problem -- the direct response "holy trinity," says Heroux.

The product also must get lucky.

The Wonder Hanger, which claims to increase hanging space, took off as the economy tanked and people downsized. Twin Draft Guards sell best during snow storms that drive people inside but don't knock out power.

"I pray for cold weather," says Heroux.

Although a direct response company may take years to bring a hopeful to market, the next ShamWow gets only a couple of weeks to prove itself. If an infomercial doesn't produce, the product flames out. No analyzing. No rejiggering. No looking back.

"We test 50 new products a year: 45 will fail in the first couple of weeks," says Khubani.

Price

Infomercial products are priced to "charm," says William Poundstone, author of Priceless: The Myth of Fair Value (Hill and Wang) and a blogger about the psychology of buying and selling.

"The human mind has a limited capacity to deal with numbers when you're making a decision," says Poundstone.

Items that cost $19.99 seem like a bargain compared to $20. Four easy payments of $49.95 sound much cheaper than $200. Pesky "shipping and handling" fees, which can double the price, almost don't count until your credit card statement arrives.

"You don't really notice shipping and handling charges until the very end" of the ordering process says Poundstone. "Once you've invested all that time, you just want to get it over with."Pitch and Pitchmen

Direct response products are all different, but all infomercials are basically the same.They establish a human need (better health, saving money), introduce the solution, throw in something -- or three -- for free but require the buyer to "act now."

Rinse and repeat.

"They really have the same rhythm, the same beat," says Poundstone. "They don't let much time pass without throwing in something free. Once a minute, they come up with something new you didn't expect."

"You will stick to your guns until three people say something different, and then you figure, 'I've got to go along'," Poundstone says. "We're all susceptible to these psychological tricks."

Pitch people are either warm and friendly, shrill and hard to ignore, common or authoritative.

The late Billy Mays shouted the virtues of OxiClean with such urgency that viewers could not look away. British pitchman Anthony "Sully" Sullivan is so determined that he recently set himself on fire to sell Cold Fire, a new extinguisher-in-a-can.

Infomercials for exercise, weight loss and heath products invariably feature a white-jacketed doctor talking science babble that "proves" the item works. Some of these professionals invented or helped develop the product. Some are paid thousands for their endorsements. Some are just out of medical school or have lost their licenses, says Remy Stern, author of But Wait ... There's More (Collins Business), which looks at the As Seen on TV industry.

"It's hard to find a credible doctor who is willing to endorse a back cure all on television," Stern says. "There are decent products and complete shams. And there's no way to tell one from another."

Never Say Always

Ultimately, an infomercial's success is as much Kismet as calculation.

The Comfort Wipe, a 2008 product that Khubani thought had so much potential, was one of his most spectacular flops.

The plastic wand was designed to help overweight or elderly people wipe their behinds. Its infomercial -- "The first improvement to toilet paper since the 1880s" -- inspired laughs and parodies, but not sales.

"Only 100 people ordered it, and 1 million people watched it on YouTube," says Khubani.

What went wrong with Comfort Wipe?

"You're guess is as good as mine," he said.

Lightning struck with PedEgg, which Telebrands developed as an alternative to the micro cheese graters people were using to remove foot callouses.

"People were cheese grating their feet," says Khubani. "We took that idea and turned it into PedEgg."

The palm-sized foot filer so far has grossed more than $300 million.

"Our hunch was correct," says Khubani, though he isn't certain what alchemy of need, design and pitch is responsible for the success.